Translocation of 14C-sucrose in Relation to Changes in Carbohydrate Content in Rose Corollas Cut at Different Stages of Development

Abstract

The dry matter and carbohydrate contents of intact growing 'Sonia* rose corollas were measured from an immature bud to full expansion of the petals. Reducing sugars and starch, but not sucrose, accumulated throughout most of the corolla development. These findings were compared with the carbohydrate changes in the corollas of flowers cut at different stages and allowed to age with their stems either in water or in a sucrose-containing solution. For a few days after cutting the carbohydrate metabolism of the cut flower roughly paralleled that of the intact flower until starch hydrolysed to maintain the soluble carbohydrate pool. Feeding with the sucrose solution maintained the soluble carbohydrate levels and retarded the hydrolysis of starch. The cut flowers were fed with 14C-sucrose and the labelled metabolites in the leaves and flowers were analysed. Active incorporation of 14C into ethanol-soluble carbohydrates, starch and ethanol-insoluble material was found indicating that an active anabolic phase precedes the catabolic phase during the senescence of the cut flower. The findings are discussed in relation to the source-sink hypothesis of flower development, with regard to the senescence and growth of the corollas of cut and intact flowers respectively.